Windows Phone 8 brings full support for the Near Field Communication technology ( NFC ) and both flagship phones - the Lumia 920 and the HTC 8X - have it. This technology allows small packets of data to be sent across short distances. It makes things like "tap+send" possible where you can send pictures, links, and all sorts of stuff just by taping two phones together. It also makes pairing devices such as a Bluetooth headset really easy.
Microsoft has shown how this makes sharing stuff really easy between two Windows Phone but what's really cool is that the basic standard is the same industry wide. Which means basic functions are cross-platform. As you can see in the video above from WPCentral, this lets users transfer links and contacts between a Windows Phone and an Android phone. Unfortunately, pictures and other data isn't supported cross-platform though they would work just fine between two phones running the same OS.
Still, this is a real cool feature that will bring people together. Unless you're an iOS user as you don't have NFC. Sorry.